Installation 
3/07  UDC3500 Universal Digital Controller Product Manual  35 
 
1 
Electromechanical relays are rated at 5 Amps @ 120 Vac or 240 Vac or 30 Vdc.
Customer should size fuses accordingly. Use Fast Blo fuses only.
To terminal 
7 (N.C.) or 9 (N.O.)
 Relay Load
1 
Load 
 
Supply 
 
Power
 
L1 
L2/N
 4
 
 5 
 7 
 8 
 9 
28 
29 
30 
31 
32 
33 
34 
35 
36 
 6 
N.C.
N.O.
 
Figure 2-14 Output #2 – Electromechanical Relay Output 
See Table 2-6 and Table 2-7 for other information about output types. 
 
 
If the load current is less than the minimum rated value of 20 mA, then there may be residual voltage across both 
ends of the load even if the relay is turned off.  Use a dummy resistor as shown to counteract this.  The total 
current through the resistor and the the load must exceed 20 mA.  Solid State Relays are zero-crossing type. 
2
 
1
 
Solid State relays are rated at 1 Amp at 25°C and derated linearly to 0.5 Amp at 55°C.  Customer should size 
fuse accordingly. Use Fast Blo fuses only. 
L1
 
L2/N
 4
 
 5
 
 7
 
 8
 
 9
 
28
 
29 
30
 
31 
32
 
33
 
34
 
35
 
36
 
 6
 
N.O.
2
 
Relay Load
 
Load 
 
Supply 
 
Power
 
Dummy Resistor
1
 
Figure 2-15 Output #2 – Solid State Relay Output 
See Table 2-6 and Table 2-7 for other information about output types.